package util;

import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;

import javax.swing.filechooser.FileFilter;

/**
 * A convenience implementation of FileFilter that filters out all files except
 * for those type extensions that it knows about.
 * 
 * Extensions are of the type ".foo", which is typically found on Windows and
 * Unix boxes, but not on Macinthosh. Case is ignored.
 * 
 * Example - create a new filter that filerts out all files but gif and jpg
 * image files:
 * 
 * JFileChooser chooser = new JFileChooser(); ExampleFileFilter filter = new
 * ExampleFileFilter( new String{"gif", "jpg"}, "JPEG & GIF Images")
 * chooser.addChoosableFileFilter(filter); chooser.showOpenDialog(this);
 * 
 * @version 1.9 04/23/99
 * @author Jeff Dinkins
 */
public class FiltroFichero extends FileFilter
{
	private Hashtable<String, FiltroFichero> filters = null;

	private String description = null;

	private String fullDescription = null;

	private boolean useExtensionsInDescription = true;

	/**
	 * Creates a file filter. If no filters are added, then all files are
	 * accepted.
	 * 
	 * @see #addExtension
	 */
	public FiltroFichero()
	{
		this.filters = new Hashtable<String, FiltroFichero>();
	}

	/**
	 * Creates a file filter that accepts files with the given extension.
	 * Example: new ExampleFileFilter("jpg");
	 * 
	 * @see #addExtension
	 */
	public FiltroFichero( String extension )
	{
		this(extension, null);
	}

	/**
	 * Creates a file filter that accepts the given file type. Example: new
	 * ExampleFileFilter("jpg", "JPEG Image Images");
	 * 
	 * Note that the "." before the extension is not needed. If provided, it
	 * will be ignored.
	 * 
	 * @see #addExtension
	 */
	public FiltroFichero( String extension, String description )
	{
		this();
		if (extension != null) addExtension(extension);
		if (description != null) setDescription(description);
	}

	/**
	 * Creates a file filter from the given string array. Example: new
	 * ExampleFileFilter(String {"gif", "jpg"});
	 * 
	 * Note that the "." before the extension is not needed adn will be ignored.
	 * 
	 * @see #addExtension
	 */
	public FiltroFichero( String[] filters )
	{
		this(filters, null);
	}

	/**
	 * Creates a file filter from the given string array and description.
	 * Example: new ExampleFileFilter(String {"gif", "jpg"}, "Gif and JPG
	 * Images");
	 * 
	 * Note that the "." before the extension is not needed and will be ignored.
	 * 
	 * @see #addExtension
	 */
	public FiltroFichero( String[] filters, String description )
	{
		this();
		for (String element : filters)
			// add filters one by one
			addExtension(element);
		if (description != null) setDescription(description);
	}

	/**
	 * Return true if this file should be shown in the directory pane, false if
	 * it shouldn't.
	 * 
	 * Files that begin with "." are ignored.
	 * 
	 * @see #getExtension
	 * @see FileFilter#accepts
	 */
	@Override
	public boolean accept(File f)
	{
		if (f != null)
		{
			if (f.isDirectory()) return true;
			String extension = getExtension(f);
			if (( extension != null )
					&& ( filters.get(getExtension(f)) != null )) return true;;
		}
		return false;
	}

	/**
	 * Return the extension portion of the file's name .
	 * 
	 * @see #getExtension
	 * @see FileFilter#accept
	 */
	public String getExtension(File f)
	{
		if (f != null)
		{
			String filename = f.getName();
			int i = filename.lastIndexOf('.');
			if (( i > 0 ) && ( i < filename.length() - 1 ))
				return filename.substring(i + 1).toLowerCase();;
		}
		return null;
	}

	/**
	 * Adds a filetype "dot" extension to filter against.
	 * 
	 * For example: the following code will create a filter that filters out all
	 * files except those that end in ".jpg" and ".tif":
	 * 
	 * ExampleFileFilter filter = new ExampleFileFilter();
	 * filter.addExtension("jpg"); filter.addExtension("tif");
	 * 
	 * Note that the "." before the extension is not needed and will be ignored.
	 */
	public void addExtension(String extension)
	{
		if (filters == null) filters = new Hashtable<String, FiltroFichero>(5);
		filters.put(extension.toLowerCase(), this);
		fullDescription = null;
	}

	/**
	 * Returns the human readable description of this filter. For example: "JPEG
	 * and GIF Image Files (*.jpg, *.gif)"
	 * 
	 * @see setDescription
	 * @see setExtensionListInDescription
	 * @see isExtensionListInDescription
	 * @see FileFilter#getDescription
	 */
	@Override
	public String getDescription()
	{

		if (fullDescription == null)
			if (( description == null ) || isExtensionListInDescription())
			{
				fullDescription = description == null ? "(" : description
						+ " (";
				// build the description from the extension list
				Enumeration<String> extensions = filters.keys();
				if (extensions != null)
				{
					fullDescription += " ." + extensions.nextElement();
					while (extensions.hasMoreElements())
						fullDescription += ", ." + extensions.nextElement();
				}
				fullDescription += ")";
			}
			else fullDescription = description;
		return fullDescription;
	}

	/**
	 * Sets the human readable description of this filter. For example:
	 * filter.setDescription("Gif and JPG Images");
	 * 
	 * @see setDescription
	 * @see setExtensionListInDescription
	 * @see isExtensionListInDescription
	 */
	public void setDescription(String description)
	{
		this.description = description;
		fullDescription = null;
	}

	/**
	 * Determines whether the extension list (.jpg, .gif, etc) should show up in
	 * the human readable description.
	 * 
	 * Only relevent if a description was provided in the constructor or using
	 * setDescription();
	 * 
	 * @see getDescription
	 * @see setDescription
	 * @see isExtensionListInDescription
	 */
	public void setExtensionListInDescription(boolean b)
	{
		useExtensionsInDescription = b;
		fullDescription = null;
	}

	/**
	 * Returns whether the extension list (.jpg, .gif, etc) should show up in
	 * the human readable description.
	 * 
	 * Only relevent if a description was provided in the constructor or using
	 * setDescription();
	 * 
	 * @see getDescription
	 * @see setDescription
	 * @see setExtensionListInDescription
	 */
	public boolean isExtensionListInDescription()
	{
		return useExtensionsInDescription;
	}
}
